The present invention relates to a system and method for updating and enhancing a geographic database, and more particularly, the present invention relates to a system and method for updating and enhancing a geographic database based on feedback from field use of the geographic data.
Computer-based navigation systems for use on land have become available in a variety of forms and for a variety of applications. One exemplary type of system uses a geographic data set, a navigation application, and optionally, a positioning system. The geographic data set includes information about the positions of roads and intersections in or related to a specific geographical area, and may also include information about one-way streets, traffic signals, stop signs, turn restrictions, street addresses, alternative routes, hotels, restaurants, museums, stadiums, offices, automobile dealerships, auto repair shops, etc.
The optional positioning system may employ any of several well-known technologies to determine or approximate one""s physical geographic location. For example, the positioning system may employ a GPS-type system (global positioning system), a xe2x80x9cdead-reckoningxe2x80x9d-type system, or combinations of these, or other systems, all of which are known in the art.
The navigation application portion of the navigation system is a software program that uses the detailed geographic data set and the positioning system (when employed). The navigation application program may provide the user with a graphical display (e.g. a xe2x80x9cmapxe2x80x9d) of a specific location in the geographical area. The navigation application may provide the user with data indicating his own location and specific directions to locations in the geographical area from wherever he is located.
Computer-based navigation systems may exist as a single unit that may be installed in a vehicle, or even carried by persons. The navigation application and geographic data set may be provided as software products that are sold or licensed to users to load in personal computers. Systems operating on personal computers may be stand-alone or connected by a communication link to a central or regional system. Organizations, such as trucking companies, package delivery services, and emergency dispatch units may employ navigation systems to track fleets and ensure the quickest routes to destinations. The navigation systems may also be made available on-line from a central system to multiple users on an xe2x80x9cas neededxe2x80x9d basis, or from on-line services such as services available on the Internet and private dial-up services.
Individual users can use navigation systems to obtain directions to a desired destination thereby reducing travel time and expenses. The directions can include detours around construction delays. Directions may be provided to street addresses, intersections, or to entities by name, such as to restaurants, hotels and service stations. One potential obstacle to providing enhanced features with a navigation system is the difficulty in maintaining up-to-date information in the geographic data set . A publisher of geographic data may obtain the information that becomes part of geographic data sets from field personnel sent to the locations to record the information or from aerial photographs or municipal records or other sources. Geographic information, however, becomes outdated as new roads are built, existing roads are changed, traffic signals are installed, businesses change their hours of operation, new businesses open, existing businesses close, etc. When changes occur, data in the geographic data set becomes inaccurate and its utility is thereby lessened.
Information identifying changes are collected using the same techniques as described above. Once the information regarding changes is collected, it is incorporated into a master geographic data set. The publisher of geographic databases then periodically distributes updated geographic data reflecting the changes to end-user. However, the process of acquiring information regarding changes is time-consuming and expensive. Moreover, existing methods of acquiring updated data may become increasingly expensive as geographic databases become more detailed and extensive in scope.
Another limitation with existing methods of data acquisition is accuracy. Even with high quality aerial photographs and other existing collection methods, the geographic coordinates of features may not always be entered in the database with a high level of precision. While existing methods are generally adequate to provide geographic data of sufficient accuracy for vehicle positioning in route guidance applications, greater geographical accuracy may be required for certain other applications, such as vehicle control.
Accordingly, a system and method are desired that would provide for a more efficient acquisition of information reflecting changes and corrections in geographic areas to navigation systems. Further, a system and method are desired that allow the accuracy of the data in a geographic database to be enhanced.
In view of the above, a first aspect of the present invention is directed to a system for updating, enhancing and/or refining a geographic database. A geographic database includes data representing physical features in the geographic region, and, optionally, attributes of such features. The system includes a plurality of data collecting sensors. Each of the data collecting sensors is installed in a separate one of a plurality of vehicles each of which is capable of traveling on roads in a geographic region. Each of the data collecting sensors provides outputs indicative of one or more features in the geographic region as the vehicle in which it is installed travels on the roads in the geographic region. A computer program executes a feedback process on the geographic database using the outputs of the data collecting sensors. A first part of the feedback program compares the outputs of the data collecting sensors to the data identifying the physical features and provides results representative of the comparisons. A second part of the feedback program is responsive to the results from the first part and determines the significance of the comparisons. A third part of the feedback program modifies the data in the geographic database based upon the significance determined by the second part of the program.
In a further aspect of the system, the data in the geographic database representing physical features in the geographic region are updated, enhanced, or refined based upon the significance determined by the feedback program.
In another aspect of the invention, the data which has been updated, enhanced, or refined, is used to provide updated, enhanced, or refined data in end-user vehicles, some of which may include the vehicles in which data collecting sensors have been installed.
According to another aspect of the invention, sensors in end-users"" vehicles are calibrated to high levels of accuracy using the data which has been updated, enhanced or refined using a feedback process.
According to still another aspect of the invention, an out-of-calibration sensor in an end-user""s vehicle is detected and re-calibrated using the data which has been updated, enhanced or refined using a feedback process.
In yet still another aspect of the invention, using a feedback process, levels of confidence of accuracy are assigned to data in the geographic database representing physical features in the geographic region, thereby enabling the data to be used for purposes requiring high levels of confidence.
In the aspects mentioned above, the data collecting sensors may be used to sense the geographic position of the vehicle (derived from GPS, dead-reckoning, or other positioning systems), vehicle speed, road gradient, lane width (derived from radar, and other similar systems), signage (derived from cameras), road direction (derived from an on-board compass or other heading-determining means), and various other physical features. The data in the geographic database may represent roads (or road segments) and their positions, as well as other attributes relating to roads.
In another aspect, the present invention is directed to a method of updating a geographic database by the steps of storing road data that includes a plurality of map positions in the geographic database. A plurality of actual positions traveled is determined by a vehicle by repeatedly sensing actual positions while the vehicle moves. At least a portion of the plurality of actual positions is matched with a plurality of map positions in the geographic database. A position difference is calculated between each actual position in the plurality of actual positions and the plurality of map positions. Each actual position for which the position difference exceeds a predetermined tolerance level is stored as a plurality of unmatched positions.